Vision in fishes and crustaceans is a fascinating and understudied area. In past decades, there were far more studies on the visual systems of sea-dwelling creatures, but with the push towards applied or translational research, the number of reports in these species have dropped off, much to our detriment as one never knows where the applications of basic research will pay off.

At the same time, the whole study of bioluminescence and vision is an interesting examination of how organisms use bioluminescence for mating, warning or aposematism, crypsis or counter-illumination and predation. It is explicitly a visual phenomenon and as such, has informed a variety of investigations into biomedical, commercial and military applications.

From their abstract: “Bioluminescent taxa comprised two species of anemone (Actinaria), a new genus and species of flabellate Parazoanthidae (formerly Gerardia sp.) (Zoanthidea), three sea pens (Pennatulacea), three bamboo corals (Alcyonacea), the chrysogorgiid coral Chrysogorgia desbonni (Alcyonacea), the caridean shrimp Parapandalus sp. and Heterocarpus ensifer (Decapoda), two holothuroids (Elasipodida and Aspidochirota) and the ophiuroid Ophiochiton ternispinus (Ophiurida). Except for the ophiuroid and the two shrimp, which emitted blue light (peak wavelengths 470 and 455 nm), all the species produced greener light than that measured in most mesopelagic taxa, with the emissions of the pennatulaceans being strongly shifted towards longer wavelengths. In situ observations suggested that bioluminescence associated with these sites was due primarily to light emitted by bioluminescent planktonic species as they struck filter feeders that extended into the water column”.

The authors of the second paper looked at how crustaceans locate food and determined that they use ultraviolet vision and color discrimination to distinguish the plankton they feed on which bioluminesces in the blue spectrum and the corals that it hunts upon bioluminesce in the blue/green and green spectra. The authors used deep sea submersibles to examine and collect crab species. On collected specimens, they flashed different wavelengths and intensities of light and determined that all deep-sea crab species are sensitive to blue light and two species in particular are sensitive to both blue and ultraviolet light.

About Webvision

Webvision summarizes recent advances in knowledge and understanding of the visual system through dedicated chapters and evolving discussion to serve as a clearing house for all things related to retina and vision science.